The front trains of vehicles usually incorporate a suspension arm which allows the wheel hub of the vehicle to be linked to the chassis, comprising a body provided with three securing points consisting of a ball joint on the wheel side and two silent-blocks on the side of the chassis which result in this link being mobile and the vehicle having independent suspension on each wheel. There are different types of suspension arm depending on the type of suspension of the vehicle (McPherson or conventional) and on the materials employed.
Forged arms are used with McPherson suspension and they consist of an arm on which the ball joint is machined and the silent-blocks are mounted.
The sheet metal arms are employed both in McPherson suspensions and in conventional suspensions consisting of the assembling of two pieces stamped from sheet metal, welded to form a box, the material employed has to be good quality with a high elastic limit to guarantee that deformations of the arm are not produced as a result of the impacts inherent in the suspension.
In these suspension arms in sheet metal a decrease in weight is achieved with respect to the forged arm, however they usually lack the adequate amount of mass to furnish the required inertia and mechanical strength.
On the other hand, suspension arms can be designed in aluminium, which, with less weight assure the same functional characteristics provided with other materials.
In the Patent of Invention EP 0401547 a single triangular suspension arm can be found which has at one of its vertices a ball joint which connects with the wheel strut holders and which has individual silent-blocks on the other two vertices thereof in articulations which pivot with respect to the chassis.